On 12/01/11 13:36, Steve wrote:
-------- Original-Nachricht --------
Datum: Wed, 12 Jan 2011 13:47:00 +0100
Von: John Adams<mailingli...@belfin.ch>
An: postfix-users@postfix.org
Betreff: Re: Network Ideas
Am 12.01.2011 12:03, schrieb Jonathan Tripathy:
On 12/01/11 10:45, John Doe wrote:
From: Jonathan Tripathy<jon...@abpni.co.uk>
While your idea would work in HA mode, would that cause any problems
if both
postfix servers were used at the same time? (i.e. load balanced)
In fact I may be able to answer my own question by saying yes, it
would cause
a problem as you're not supposed to write to a DRBD secondary...
I saw some active-active DRBD howtos; but they used filesystems
likeOCFS2 or GFS
and such...
http://www.sourceware.org/cluster/wiki/DRBD_Cookbook
But I am no expert...
JD
If I used a nfs cluster, I could use both postfix server at the same
time, couldn't i?
these questions you should really ask in the heartbeat/drbd
mailinglist(s).
Just one hint: think about complexity in an active-active cluster
running ocfs2 and mail. Think about file locking.
Building this is one thing. Managing the unexpected afterwards is
another thing.
I run a two node mail server using GlusterFS with replication. It is ultra easy
to setup. File locking in mail environments is no big issue. Mostly mail
arrives on one of the mx nodes, gets processed and then passed to the delivery
agent, the delivery agent then saves the mail (in my case maildir format) into
the final destination. In the whole processing there is almost no locking
involved since the mail saved in the maildir has an unique number and that
alone mostly avoids the need for locking. The POP/IMAP server does then
indexing and this is the place where locking is/can be involved. But a good
IMAP/POP server can handle that (dovecot can).
The whole storage part works so well that I often forget that it is clustered.
The good thing about GlusterFS is that I can add as many active nodes as I like.
The only part where you have to take care about a clustered mail servers or a
n-node mail server setup is more the other things that you glue into the mail
server. Things like greylisting, antispam, mailing list software, etc... This
kind of stuff requires to be cluster aware. The storage is the lesser problem
IMHO.
Thanks Steve, excellent info
As for the antispam, greylisting and av things, they will be on
different servers which are related to the cluster, so I think I'm good
there.
As for the GlusterFS, I take it this would replace DRBD, Heartbeat and
NFS in my proposed setup? Have you got any good links that you would
recommend to setting up such a setup?
Thanks
